Stephen g



S. G. SKINNER.

COMPOUND AIR PUMP.

APPLICATION FILIED mm: 28. 1919.

Patented Nov. 25, 1919.-

sraans ra'rnnr orrion.

STEPHEN G. SKINNER, OF CHICAGO, ILLINOIS,

COMPOUND AIR-PUMP.

panacea.

This invention. relates to a compound air.

pump of the type comprising three concentrically disposed pump tubes of diii'erent diameters, the outer and inner tubes or cylinders being stationary, whereas the intermediate tube or piston rod is provided with an operating handle for effecting its reciprocation. My present invention is concerned with the. provision of a pump of this type that is more rugged in construction and generally more satisfactory in operation than any of the devices of this type which have preceded it. The improvements herein shown and claimed are particularly applicable to the form of pump described and claimed in my earlier Patent No. 867,616, granted Oct. 18, 1907.

In the accompanying drawings illustrating my invention:

Figure 1 is a vertical sectional view of a compound air pump embodying the improvements of my invention;

Fig. 2 is an enlarged axial sectional view illustrating the piston at the lower end of the tubular piston rod, and the combined check valve and packing device also carried at the lower end of the tubular piston rod;

Fig. 3 is a bottom plan view of the hollow pressed metal member forming a part of the combined check valve and packing device;

lower end of the outer pump cylinder 11.

The upper portion of the base is provided with an internally threaded central bore, into which is threaded the lower end of the inner cylinder 12. Cylinders 1'1 and 12 are both stationary with respect tothe base.

The base carries a nipple connecting with Specification of Letters Patent.

Application filed. June 28, 1919.

Patented Nov. 25, 1919.

Serial No. 307,332. r

the usual hose 13, and is suitably tapped and drilled to provide a passage between the bot tom of the cylinder 12 and the hose 13, which hose is provided witlr the usual coupling 14 for attaching it to the valve of a pneumatic tire.

The inner tube or cylinder 12 is externally threaded at its upper end, as is most clearly shown in Fig. i, and theaded thereon is a cylindrical metal block 15, provided with a hollow central upwardly projecting boss- 16 provided with external screwthreads. Threaded upon the boss 16 is a hollow pressed metal member 17, the top wall of which is provided with a central aperture 18. Carried by the block 15 and securely clamped thereto by the lower end of the pressed metal member 17 is an upwardly facing cup leather 19, the side wall of which snugly fits the inner cylindrical surface of the tubular piston rod 20. It will be noted that the upper end of the tubular piston rod is closed by a cylindrical block 21, to which the operating handle 22 is secured, as shown. A fiber washer 23 is preferably disposed between the upper surface of the cup leather 19 and the lower end of the pressed metal member 17. Disposed within the hollow central boss 16 of the cylindrical block 15 is a plunger 24, having a disk-like head at its upper end. A coiled spring 25 acting between the head of the plunger and i the upper end of the inner pump cylinder 12 tends to move the plunger head into engagement with the top wall of the pressed metal member 17. Freely disposed within the pressed metal member 17 and interposed between the head of plunger 24 and the top wall of the pressed metal member is a leather disk 26, which is of less diameter than the inner diameter of the hollow pressed metal member 17. Thus it will be noted that the disk 26 normally closes the passage which would otherwise be provided by the aperture 18.

Referring now particularly to Fig. 2, it will be noted that at its lower end the tubular piston rod 20 is provided with a collar 27, which is rigidly attached to the piston rod and provided at its lower end with a radial flange. That portion of the collar which incloses the threaded lower end of the tubular piston rod is spaced from the latter to enable the internally threaded upper end of a pressed metal housing 28 to be threaded upon thelower end of the piston rod. It

will be noted that the pressed metal housing.

28 is conformed to providean annular shoulder 29, upon which rests a metal washer 30,

between which and the flange ofthe' collar.

27 is securely clamped a downwardly facing cup leather 31, the side Wall of which snugly fits the inner cylindrical surface of the outer pump cylinder 11. 7

' While the housing 28 constitutes one of the elements for supporting the cup leather 31, its principal function is to house and support a combined check valve and packing I device, which will now be described. It wil be noted that the bottom of the housing 28 is 7 leather disk 34, which rests on the cup leather 33 and, similarly to the cup leather, snugly fits the outer surface of the inner cylinder 12. The cup leather 33 and disk 34 are securely held in position by a pressed metal member 35, the bottom wall of which is provided with alarge opening, preferably of greater. diameter than the outside dianieter of the cylinder 12. The member 35 is provided with apertures 36, 36, in its side wall, and at its upper end is externally screwthreaded to cooperate with the internal screwthreads of the housing 28. It will I be understood that all of the parts contained within the housing 28 are assembled therein, as shown, before the housing is threaded upcpn the lower end of the tubular piston ro In addition to the central aperture 32, the

bottom wall of the housing 28 is provided with a plurality of apertures 37,37, located adjacent the periphery of the upwardly fac ing cup'leather 33. I 7

It will be noted that the upper end of the i outer pump cylinder 11 is provided with a cap '38, with which the tubular piston rod 20 has a sliding fit, the said cap being preferably apertured at 39, at all times to afford communication between the upper end of the outer cylinder 11 and the atmosphere. En-

, circling the lower end of the inner pump cylinder 12 and resting upon the base, 10 is washer, which, by its engagement with the bottom wall ofthehousing 28, serves as a cushion for thetubular piston rodand parts 7 carried thereby at the-lower end of their ow var strok c the housing 2S r The operation of the pump is as follows:

When the tubular piston rod isdrawn upwardly, air entering the upper end of the outer pump cylinder llpasses around the downwardly facing cup leather 31, and fills that portion of the cylinder 11 below the cup leather with air at atmospheric pressure.

On the down stroke of the tubular piston rod, air under pressure acting-against the inner surface of the cup leather '31 forces the latter tightly against the inner surface of the cylinder 11 and prevents the escape of pressure at this point. Downward move ment of the piston rod, therefore, results in cup leather. 19 to that portion of the tubular piston rod above the piston carried by the upper end of the inner pump cylinder 12,. this being the only path this air can take, since the upwardly facing cup leather33 now acts as a check valve toprevent air I from passing from. the tubular piston rod back into the outer cylinder 11. On thenext 7 down stroke of thetubularpiston rod,the air in the upper end of the latter is forced past the leather disk valve 26 into. the upper end of the inner pump of the cylinder 12,

from whence it is conveyed-by hose 13 to the tireto be inflated.

The foregoing, I believe,'will for the purposes of this specification sufliciently describe the operation and function of my imeproved air pump. r It will be noted that the. check valves tubular piston rod and thejinner cylinder 12 comprise valve elements of'leather, to-

which control communication between the wit, upwardly facing cu leather-B3 and-the I 7 leather disk valve 26/ valves are foundto "function much more satisfactorily than any other form of; check hese leather check valve suitable for the purpose, with which I-am familiar. It will be notedthat .both of these' leather checkvalve elements are? entirely inclosed and protected by the housings 28 and-17 respectively. Moreover, the upwardly facing cup leather 33 performs a 7 double function. It not only constitutes a aleather disk 10, constituting a-bumpeiw check valvercontrolling communication between cylinder 11 and piston rod 20, but also cylinder 12 passes through; the lQQtQQm of- Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1. In an air pump comprising fixed inner and outer cylinders and a tubular piston rod extending downwardly between the upper ends of the said inner and outer cylinders, a piston carried by the upper end of the inner cylinder, snugly fitting the inner surface of the tubular piston rod, a check valve seating against pressure in the tubular piston rod above said piston, controlling communication between the inner cylinder and saidtubular piston rod, a downwardly facing cup leather carried by the lower end of the tubular piston rod, and a combined check valve and packing device comprising a hollow member carried by the lower end of the tubular piston rod, said-hollow member having a cylindrical inner surface and a substantially flat bottom having a central aperture through which the inner cylinder "extends, a centrally apertured upwardly facing cup leather fitting around the inner cylinder and snugly fitting thebottom and cylindrical inner surface of said hollow member, together with an aperture in the bottom of said hollow member, near the periphery of said upwardly facing cup leather, and means for clamping said upwardly facing cup leather to the bottom of said hollow member.

2. In an air pump comprising fixed inner and outer cylinders and a tubular piston rod extending downwardly between the upper ends of the said inner and outer cylinders, a piston carried by the lower end of the tubular piston rod, snugly fitting the inner surface of the outer cylinder, together with a combined check valve and packing device comprising a hollow member fitted to the lower end of the tubular piston rod, a bot tom for said hollow member having a cen tral aperture through which the inner cylinder extends, the inside of said hollow member communicating with the inside of the tubular piston rod, an upwardly facing cup leather centrally apertured and snugly fitting the outer surface of the inner cylinder and fitting against the bottom and side wall of said hollow member, together with an aperture in the bottom wall of said hollow member adjacent the periphery of said upwardly facing cup leather, and means for holding the cup leather against the bottom of said hollow member.

3. In an air pump comprising fixed inner and outer cylinders and a tubular piston rod extending downwardly between the upper ends of said inner and outer cylinders, a downwardly facing cup leather carried by the lower end of said tubular piston rod, and a combined check valve and packing device carried by the lower end of said tubular piston rod, comprising a hollow member having a centrally apertured bottom through which the inner cylinder extends, an upwardly facing cup leather resting on the bottom of said hollow member and snugly fitting the outer surface of the inner cylinder and the side wall of the hollow member, together with means for holding the upwardly facing cup leather against the bottom of said hollow member. I

4. In an air pump comprising fixed inner and outer cylinders and a tubular piston rod extending downwardly between the upinder and the side wall of the hollow mem- I ber, together with means for holding the upwardly facing cup leather against the bottom of said hollow member, and a plurality of apertures in the bottom of said hollow member, adjacent the periphery of said upturned cup leather.

5. In an air pump comprising fixed inner and outer cylinders and a tubular piston rod extending downwardly between the upper ends of said inner and outer cylinders, a downwardly facing cup leather carried by the lower end of said tubular piston rod, and a combined check valve and packing. devicecarried by the lower end of said tubular piston rod, comprising a hollow member having a centrally apertured bottom through which the inner cylinder extends, an upwardly facing cup leather resting on the bottom of said hollow member and snugly fitting the sidewall thereof, a disk of yielding material centrally apertured and fitting snugly around said inner cylinder, and means for clamping said disk and upwardly facing cup leather to the bottom of said hollow member.

6. In an air pump comprising fixed inner and outer cylinders and a tubular piston rod extending downwardly between the upper ends of the said inner and outer cylinders, means at the lower end of said tubular piston rod afiording a tight fit between the lower end of the piston rod and said outer cylinder, together with a check valve between the outer cylinder and the tubular piston rod, comprising a cup leather centrally apertured and snugly fitting the outer surface of the inner cylinder.

7 In an air pump comprising fixed inner and outer cylinders and a. tubular piston rod extending downwardly between the upper ends of the said inner and outer cylincarried by the piston rod, having an apertured bottom through which the inner cylinder extends, and a cup leather centrally apertured and fitting around said inner cylinder and snugly fitting the side wall of said hollow member] 8. In an air pump comprising fixed inner and outer cylinder and a tubular piston rod extending downwardly between the upper ends of said inner and outer cylinders, means at the lower end of said tubular piston rod affording a tight fit between the lower end of the piston rod and said outer cylinder, together with a check valve between the outer cylinder and said tubular piston rod, comprising a hollow member car ried by. the piston rod, having an apertured bottom through which the inner cylinder extends, and a cup leather centrally apertured and fitting around said inner cylinder and snugly fitting the side wall of said hollow 7 member, together with means having threaded engagement with said hollow mem-j her, for clamping said cup leather to the bottom of the hollow member. 7

' 9. In an air pump comprising fixed inner and outer cylinders and a tubular piston rod extending downwardly between the upperger toward said top wall, and a disk of yielding material, of less diameter than said hollow member, freely resting on .thetop' ofvsaid plunger, and normally closing said aperture.

In witness whereofI hereunto subscribe my name this 26th day of June, 1919.

lVitnesses v I ROBERT F. BRAGKE,

MCLGAVLEB.

STEPHEN G. sKrNN R, 

